Hypothermia

Hypothermia occurs when your body loses heat faster than it can produce it,
causing your core body temperature to fall. When the core temperature drops
below 78˚ Fahrenheit, the body dies. Hypothermia is often induced by cold, wet
conditions, such as rain, snow, sleet, or immersion in water. The outdoor temperature
does not have to be below freezing. A person may develop hypothermia when the
temperature is around 50˚ Fahrenheit and it's damp or windy.

Moisture from perspiration, humidity, and dew or rain
on bushes and trees also can soak your clothing over time, putting you
at risk in cold weather. Wet or damp clothes will draw heat out of your
body more rapidly. Wind lowers your body temperature as it evaporates
moisture from your body. Resting against cold surfaces also will draw
heat from your body.

Prevention of Hypothermia

Hypothermia can be prevented by dressing properly, by avoiding potentially
dangerous weather conditions, and by drying out as quickly as possible
when you get wet. High-calorie foods, including chocolate or dried fruits
such as raisins, provide quick energy that helps your body produce heat.

Wind chill is given in the body of this table.

The National Weather Service and Environment Canada issue a Wind Chill Advisory when wind chills are expected to reach -10° F (-23° C). A Wind Chill Warning will be issued when wind chills are expected to be -20° F (-29° C) or lower.